I realize a problem with the fight match ups. As long as Sanji is in the same area, can anyone of importance get away with attacking Nami or Robin? Unless either of these ladies get knocked someone out of his vision, I fear they'll get cheated out of their fights-of-the-arc. Which would be a shame, since I would like to see the less common fighters get a match.
Also, about Caribou, assuming each fighter only gets one major fight here, who is going to fight him? Zoro, Sanji, Luffy, and Jimbe are all taken and only they can possibly hurt logia users.. I guess it's possible that either of those guys just fight again assuming their current battles go well, or maybe Caribou gets the Van Decken treatment and gets owned quickly. Or, maybe Franky fights him with some yet-to-be-seen sea stone weapon? He was the guy to trap Caribou in a barrel, so you could say they have a rivalry going.
In fact, the rivalry's are all like this so far, simple and obvious:
Chopper: You wreck my tank, we must fight.
Zoro: You have a sword, we must fight.
Jimbe: You punch me? I kick you!
Sanji: You indirectly cause Nami to lightly fall down? Fucking killing ya.
Luffy: Too many to count.
Again, I'm waiting for someone to knock down a historical monument or state that music or whales are stupid.